I ordered a horse hair knot today from PC Woodcraft. It's a 24mm knot with a loft of 67mm. I know pretty much zero about horse hair knots. It's advertised as being "soft with backbone" but also states "if your looking for a stiff brush, this isn't it". I think I'm going to try mid 50's for loft. Anybody tried this knot? Open to suggestions about loft. Looking around I've found the loft/diameter to be varied and don't have any idea of the % mane to tail.